The invention relates to a polypeptide derived from the TSR (thrombospondin type 1 units) of SCO-Spondin for inhibiting or preventing apoptosis mediated by the cell death receptor ligands, such as TRAIL or FasL. The polypeptide of the invention comprises a sequence -W-S-A1-C-S-A2-C-G- wherein A1 and A2 are amino acid sequences comprising 1 to 5 amino acids. More particularly, the invention relates to said polypeptide for inhibiting or preventing the apoptosis associated with a disease selected from the group consisting of neurodegenerative disorders, cerebral ischemia, neuronal traumas, neuronal inflammatory diseases, and viral neurodegenerations.